Fatigue testing machine



, Search-Roam x3 18 X 3 7 l 1942- o. s. PETERS 4 FATIGUE TESTING MACHINE Filed July 16,, 1940 INVENTOR OEVI LLE S. PETEBs a. r c

FATIGUE TESTING nmonmr:

Orville S. Peters, Chevy Chase, Md., assignor to The Baldwin Locomotive Works, a corporation of Pennsylvania Application July 16, 1940, Serial No. 345,729

4 Claims.

The present invention is an improvement on the resonant fatigue tester disclosed in de Forest Patent No. 2,171,303, the operation of which has certain limitations such as the inability to test nonmagnetic materials. It is an object of my invention to provide an improved resonant fatigue tester that is adapted to test materials of all kinds and to do so with an arrangement that is simple and economical in construction, opera-' tion and maintenance. A further object is to provide an improved arrangement that has a high degree of ruggedness combined with adequate flexibility both in operation and in readily and conveniently: holding specimens in position without requiring dismantling or other interference with the resonant producing elements.

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawing in which:

Fig. 1 is a perspective of my resonant fatigue tester; and

Fig. 2 is a vertical transverse section taken substantially on the line 2---2 of Fig. 1.

In the drawing a suitable base I carries a U-shaped magnet 2 formed preferably of lam inations riveted together as at 3,.while the. winding, 4 is energized from a suitable source of alternating current having any desired frequency. This magnet is supported upon the base I through legs 5.

An armature 6 formed preferably of laminated members is secured-together and formed rigidly with the underside of a flexure plate I and as shown in Fig. 2 the armature extends downwardly within the U magnet. The flexure plate 1 consists of a reduced flexible portion 8 con necting two relatively heavy, rigid portions, the outer free one then constituting a lower vise jaw connected to the armature 6 and the inner one 9 being bolted to the base I. A specimen I!) of any desired material is adapted to be removably clamped to the free end of fiexure plate 7 as by an upper vise jaw H secured tothe flexure member by bolts l2. When the field 2 is energized it causes the vise jaws to vibrate vertically and set up a certain resonant wave in specimen ID which subjects the same to fatigue stresses. As is necessary in this type of fatigue tester two adjustable eccentric rubber rollers l3 are adapted to have slight engagement with the wheels 14 which, in turn, are pivotally supported on a frame i5 while a small finger operated worm I6 is adapted to rotate the gears l4 and rubber padsl3 toward or away from the free end of specimen ID. The stress created in the specimen is determined by measuring the specimen deflection through a vertically adjustable V-shaped end of a micrometer screw l1 until it has slight contact with the specimen ID. A frequency counter l8 as well as an electric switch [9 for the current of coil 4 may be provided.

From the foregoing disclosure it is seen that -I have provided an extremely simple and efiective structure and mode of operation whereby non-magnetic material may be supported in the vise and subjected to a resonant fatigue force set up by a magnetic source of energy imposed on the armature and the vise connected thereto, this being done uniformly for all types of specimens while still retaining the magnetic characteristics of the source and without interfering in any way with the structural elements thereof. It will of course be understood that various I changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim: a

1. A resonantqvibration fatigue testing apparatus comprising, in combination, a resiliently mounted clamp for removably holding and supporting one end of a specimen While its other end is free, and magneticmeans having a magnetically actuated element connected to said clamp to vibrate the clamp and establish a res- -ing magnetic field and a magnetic element specimen. These rollers are mounted upon gear 55 I adapted to be vibrated by said field, saidv vibrated element and clamp being connected together to constitute a unitary vibratory structure.

3. A resonant vibration fatigue tester comprise ing, in combination, a base, a fiexure plate secured thereto and having a free end constituting"- an element of a specimen vise for removably clamping and supporting one end of a specimeans for securing one of said heavy portions 10 to said base, a removable clamping element secured to the other heavy portion of said flexure member for supporting and securing one end of a specimen thereto while the other end of said specimen is free, and a magnet and armature one of which is connected to said base and the other of which forms a unitary part of said flexure member so as to vibrate in unison with the clamp and specimen. ORVILLE S. PETERS. 

